1. Field of the Invention
This invention relates to an eyeglass frame having a rim comprising two lens-holding rings, which are connected by a bridge, wherein said two rings are constituted by a top rim member, which is common to both rings and includes also the bridge, and two bottom rim members, which are separate from the top rim member and belong to respective ones of said rings and are provided each with a nose pad, and each of said bottom rim members is detachably connected to the top rim member by positive coupling means.
2. Description of the Prior Art
In conventional eyeglasses comprising two lens-holding rings, the contour of the lenses and, as a result, also the shape of the eyeglasses, is determined by the eyeglass rim and cannot be changed. A specially shaped rim is required for eyeglasses of any given shape so that a high expenditure is involved in the manufacture and stockkeeping of differently shaped eyeglass rims.
In order to avoid said disadvantages it has already been suggested (in Published German Application 1,772,401 and French Patent Specification 970,746) to provide the bottom rim portions as members which are separate from a common top rim member, which includes also the bridge, and to detachably connect said members so that it will be possible to combine one and the same top rim member with bottom rim members having different shapes and/or different colors and the overall appearance of the eyeglasses can be varied. Said known eyeglass frames have the disadvantage that the bottom rim members are joined to the common top rim member by plug pins, which extend generally in the peripheral direction of the lens-holding rings and, as a rule, do not have the strength which would be required to hold the members of the rim together so that said members must additionally be connected by means of screws and tapped brackets integrally formed with said rim members or by means of locking pins extending transversely to the plane in which the rim extends. Said additional retaining elements add to the expenditure of material and render the assembling of the eyeglass rim more complicated.
Besides, U.S. Pat. No. 2,553,496 discloses eyeglasses comprising lens-holding rings which are constituted by a common top rim member and a common bottom rim member and said two rim members are joined by a snap-action coupling, which comprises hook means extending transversely to the plane of the eyeglass rim. But if that positive coupling is designed to be re-opened, there will be a risk of an unintended separation of the two rim members under the usually occurring loads so that the lenses will then be released.